Change bullets! help plz-java-

i need some help with java. i am creating a game where i have a player and he shoot bullets. u can also change u types of bullet.
bullets are just fillOval. and change types of bullets is different colo.

i have created a class bullet. which just create one bullet.
than if player hit space bar. than create a bullet and store in arraylist.

If you change the colour, how does the existing bullet(s) know about the previous colour? to get this effect, each bullet have to know about their own colour, by saving the colour in the bullet class.
Does the Bullet class have its own bulletname variable?